2.3 Effect of Bioaccumulation on Ecosystems – Student Notes

Ø  Amphibians are valuable ______of environmental health because they’re sensitive to chemical changes.

Ø  Since the 80s the world amphibian population has ______& birth deformities have ______.

Ø  This may be due to: ______, increased UV rays, ______, habitat loss, ______.

Ø  ______: a slow build up of chemicals in the bodies of organisms.

·  If bioaccumulation occurs in a ______, it can affect every other organism in its far reaching ______.

Ø  Eg. Bioaccumulation of PCBs in the B.C. Orcas.

·  PCBs will affect the reproductive cycles of Orcas until at least 2030, even though they were banned in ‘77.

Ø  Chemicals like ______and ______& other insecticides are called ______.

·  ______contain ______, & remain in water & soil for many years (like all organic comp)

·  ______, even at low levels (5 ______) causes nervous, immune & reproductive system disorders in animals. [ppm = parts per million]

Ø  ______also ______.

·  Lead, cadmium & mercury are the most dangerous.

·  ______is not considered safe at any level, it can cause anemia, nervous & reproductive system damage.

·  ______is toxic to earthworms & causes many health problems in fish.

·  Cadmium causes ______, ______, ______

______damage in humans (exposure to cigarette smoke).

Ø  ______enters ecosystems through burning of fossil fuels, waste incineration, mining & the manufacture of batteries.

·  Coal burning adds ______of the mercury released.

·  Mercury ______in the brain, heart & kidneys of many animals (Fish ______mercury, adding risk for any organisms eating fish).

Ø  Reducing the effects of chemical pollution

·  If chemicals are trapped in the soil, they cannot enter the ______as easily.

·  ______: micro-organisms or plants are used to help clean up, and are then removed from the ecosystem.

Eg. The oil industry will often use bacteria to “eat” oil spills.

Ø  ______: the consumers in each ______receive larger doses of accumulated chemicals than the one before it.

The bioaccumulation of PCBs begins with the absorption of the chemicals by microscopic plants and algae.